Question

got a tricky one here me thinks!

I want to understand how if this Cart object gets passed by value using the model binder, then how can it effect the actual value in the session?

  public RedirectToRouteResult AddToCart(Cart cart, int productId, string returnUrl) {
        Product product = repository.Products
            .FirstOrDefault(p => p.ProductID == productId);

        if (product != null) {
            cart.AddItem(product, 1);
        }
        return RedirectToAction("Index", new { returnUrl });
    }

Hope this explains my issue!

Thanks for any assistance

details

this bold code doesn’t effect the customprofile in session

   [AllowAnonymous]
    [HttpPost]
    public ActionResult Register(RegisterModel model, CustomProfile customProfile)
    {
        if (User.Identity.IsAuthenticated)
            return RedirectToAction("Index", "Home");
        if (ModelState.IsValid)
        {
            // Attempt to register the user
            MembershipCreateStatus createStatus;


            membershipProvider.CreateUser(model, null, null, true, null,
                                          out createStatus);

            if (createStatus == MembershipCreateStatus.Success)
            {
                const string message = "You have successfully reigestered, and you are now logged in.";
                authProvider.SetAuthCookie(model.UserName, false /* createPersistentCookie */);

                var newCustomProfile = new CustomProfile(model.UserName);
                var db = new CrowdFundingDB();

                **customProfile = customProfileProvider.Create(newCustomProfile);**

Answer 1

Cart is not a value type, it’s a reference type.

Passing it as an argument doesn’t make a copy of the object, the method receives a copy of the reference to the actual object. It will access the same object through the copied reference.

See also: ByRef vs ByVal Clarification